Infusion package heat sealing filter-paper manufacture



Dec. 29, 1942. T. F. MENZEL 2,306,400

INFUSION PACKAGE HEAT SEALING FILTER-PAPER MANUFACTURE Original FiledMay 17, 1940 2 Sheets-Sheet 1 111: 2d, w, M W 0 w A 3 Qi WVENTOR,ficadorzf Veazd. BY q ATTORNEY.

Dec. 29, 1942. T. F. MENZEL 2,306,400

INFUSION PACKAGE HEAT SEALING FILTER-PAPER MANUFACTURE Original FiledMay 17, 1940 2 Sheets-Sheet 2 112 /31ia 3115 g? 7/ V/ INVENTOR.

meodaref venzel.

ATTORNEY.

Patented Dec. 29, 1942 INFUSION PACKAGE HEAT SEALING FILTER-PAPERMANUFACTURE Theodore F. Menzel, Long Island City, N. Y., as-

signor to Millie Patent Holding 00., Inc., a corporation of New YorkOriginal application May 17, 1940, Serial No.

Divided and this application December 18, 1940, Serial No. 370,588

I12 Claims.

This invention relates to the manufacture of a heat sealing sheetmaterial for packaging filled containers or bags, as for example,infusion packages like tea-balls, coffee balls and the like.

a simple method and adapted to be incorporated in inexpensive articlesof new, neat and attractive appearance, which shall be particularlysuitable for large scale production with high speed automatic bagmaking, filling and sealing machines, and which improved method ofmanufacture and sheet material shall be efficient and practical to ahigh degree.

This case is a division of my application Serial No. 335,694, filed May17, 1940 for Packaging and the manufacture of heat sealing filter sheetmaterial therefor.

Other objects of this invention will in part'be obvious and in parthereinafter pointed out.

The invention accordingly consists in the features of constructions andmethod, combinations of elements, arrangements of parts and steps in theprocess of manufacture which will be exemplified in the constructionsand method hereinafter described and of which the scope of applicationwill be indicated in the following claims.

In the accompanying drawings in which is shown various possibleillustrative embodiments of this invention;

Fig. 1 is a diagrammatic perspective. view illustrating the process formanufacturing heat sealing filter sheet material embodying theinvention:

Figs. 2, 3 and 4 show detailed enlarged sectional views of the heatsealing filter sheet material at successive progressive steps during themanufacture thereof using a filtering sheet material formed of avegetable fibrous pulp as a base layer, taken at lines 22, 3-3 and 4-4in Fig. 1;

Figs. 2a, 3a and 4a show detailed enlarged sectional views of the heatsealing filter sheet material showing successive progressive similarsteps to Figs. 2, 3 and 4, using a filter sheet material formed ofcotton staple pulp as a base layer;

Figs. 2b, 3b and 4b show detailed enlarged secterial showing successiveprogressive steps similar to Figs. 2, 3 and 4, using a filtering sheetmaterial formed of perforated parchment paper or Cellophane sheet, as abase layer;

Figs. 2e, 3e and 4c show detailed enlarged sectional views of the heatsealing filter sheet material showing successive progressive stepssimilar to Figs. 2, 3 and 4 using a cotton gauze textile sheet material,as a base layer; and

Figs. 5 and 6 are front and side elevational views, respectively, of acomplete tea-ball with string handle and tag constructed to embody theinvention. I

In practising the embodiment of the invention for manufacturing tea orcoffee balls Ill and particularly heat sealing filter sheet material Hfor constructing the container or bags I 0a thereof, a suitable filterpaper sheet in the form of base layer Ila, such as made from a vegetablefibrous pulp stock may be used, and when processed in the mannerhereinafter described forms sheet material H from which containers orbags Illa of the tea or cofiee balls III are made. The filter paperlayer lla alone preferably should have sumcient strength toretain theshape and form of the tea-ball Ill on immersion in boiling water withoutdamage or disintegration, and serves to permit readypassage'therethrough of the water of immersion for forming a brew and tostrain the filling or contents T, such as tea,

or coffee from passing out of the ball lll, said layer lla being of suchcomposition that it is insoluble, is non-toxic, and does not impart inthe slightest degree any odor or taste to the brew and has no chemicalreaction therewith.

Referring now to Fig. 1, the process of manufacturing the improved heatsealing filter sheet II is seen to consist in thinly spreading a finelydivided plastic l2 over one side llb of successive travelling surfaceportions of filter paper sheet base layer lla passing under suitablespraying or sprinkling means S, said base layer lla being preferably inthe form of a moving web or strip, a section thereof being shown in Fig.2. The plastic used may be a synthetic resin of the prenol, urea,formaldehyde, glycerol, phthalic anhydride, acetylene, rubber andpetroleum group, and provides the heat sealing means in the mannerhereinafter described. The specific group of synthetic resin hereselected to produce heat sealing filter sheet ll illustrating anembodiment of the invention is a thermosetting polymerizing resinousproduct such as powdered or finely granulated copolymer of vinylchloride and vinyl acetional views of the heat sealing filter sheet ma-5-? tate, which will leave the heat sealing filter sheet I I after beingprocessed with no part thereof that will dissolve, give off any odor,alter the taste, or otherwise impart toxic or. injurious effects as afood product when incorporated in the finished tea or coffee ball l andimmersed in boiling Water for brewing.

The base layer Iia spread with said plastic I2 over one surface I Ibthereof is next heated by any suitable means, such as heater H, to adegree sufficient only to cause the plastic I2 to flow, that is, tosoften and cohere, and in which state it is pressed between suitablerollers R or the like to form apervious film, lamina or superficialcoating I2a of. finely divided inorganic material adhering to said sideill) of the shown in Fig. 4. The degree of heat applied to said plasticI2, however, is insufficient to cause a permanent setting-of the plasticforming coating Ila. when said coating I2a is a copolymer of vinylchloride and vinyl acetate, heating temperatilre of approximately 65 C.will be found satisfactory. Because the base layer IIa used is formed ofa vegetable fibre pulp, the rolled coating I2a adheres and is retainedby an adsorption thereof around and about the pulp fibres as a perviousstructure without substantially decreasing the original porosity orpractically effecting the filtering capacity of the paper base layer Ila.

After base layer IIa with the lamina or rolled coating I2a is cooled toroom temperature it hardens, which will hereinafter be referred to aspartial fusion or being partially fused." In this state said coating Ilais dry and forms with the base layer IIa the heat sealing sheet materialI I which remains flexible and may be coiled up in rolls (not shown) inthe well understood manner, ready for use in making containers or bagsIlla for ball I0. Heat sealing sheet material II when used for the lastnamed purpose is cut into proper size for manufacturing bag IIIa whichwhen filled with the contents T, such as tea or coffee, and closed formsthe ball I0. The containers or bags I0a are each constructed with thecoating Ila side of the sheet material I I as the interior surfacethereof. The edge joints or seams l0b and top closure seam Iilc are madeby having the coating I2a portion thereof placed in face to facerelation, pressed together and heated to a fusion temperature bysuitable clamp means of any well known construction to unite the partsforming said edge joint seams I0b or closure seam IIIc sealed inpermanently fused adhesion. With coatings I2a formed of copolymer ofvinyl chloride and vinyl acetate, such permanent sealing fusion of saidseams will take place when pressed and heated to about 130 C. bysuitable clamping and heating means.

It has been found in practice that a 6 pound fibrous pulp stock sheet ofapproximately .001 inch thick forms a practical filter paper layer I lafor the purposes described herein. On said layer Ila the finely powderedcopolymer of vinyl chloride and vinyl acetate uniformly sprinkled orsprayed and partially fused" and rolled thereon provides a satisfactorypervious, dry, extremely thin coating I2a of approximately three ouncesin weight for each pound of the layer Ila and normally less than .0005inch thick.

Referring now to Figs. 5 and 6, where it is desired to provide a stringhandle I 3 of cotton strands terminated by a tag I4, the strands of thestring handle preferably may be processed with a plastic I2 to apartially fused state in the manner similar to that described above inthe manufacture of heat sealing sheet materialil.

base layer Ila, as

An end Ila of the'string'handla Il may be inserted between the coatedside face to face por tions In of said sheet material II during theformation of the top closure Joint or seams "lo, and the final sealingheat appliedsirnultaneously to anchored end Ila within the Joint seamslie and the entire joint seam IiIc for permanently fusing thereof. 1

To secure the tag II to the terminatfi'g-or free end I3b of the stringhandle I8 opposite the anchored end I3a, one side of each tag 44 mayalso be processed in the vmanner described above in the manufacture ofheat sealing sheet material I I' to provide a partially fused" coatingside, and if desired may be folded .over said procdsed string handle endI3b .therebetween. The ;,partially fused" plastic material side of saidtaI' M in face to face relation and the string har'iflcrend IIb may beunited on pressure and application of heat to a degree ffir'permanentfusion.

While the above described method of'attaching the string It to thestring handle end 'I3b is preferred, it is to be understood that suchattachment may also-be accomplished by simply pressing and permanentlyfusing the string handle end I3b to the "partial fused" coated side ofthe tag I4 without folding of the latter.

In Figs. 2a, 3a and 4a there is illustrated the results of successivesteps of the improved manufacturing process applied to a filter paperbase layer I I Ia formed of cotton staple pulp stock having an uppersurface III!) on which the said plastic I2 is thinly spread, and whichwhen heated, rolled and cooled for "partial fusion provides a lamina orsuperficial dry coating I2a as part of heat sealing filter sheetmaterial I II in the same manner as described above for the heat sealingfilter sheet material I I. The coating IIa formed on the side iIIacoheres and is retained by an absorption thereof on the portion of theside II lb of cotton staple pulp of base layer IIIa as a perviousstructure without substantially decreasing the original porosity of saidfilter paper base layer IIIa.

Although filter paper base layer I I la formed of cotton staple pulpstock has a much lower tensile strength when wet and immersed in hotwater than filter paper base layer I la of the same thickness formed ofvegetable fibre pulp stock, the addition of the superficial coating I2aon either of said layers I la or I I la increases the wet tensilestrength of each, and in the case of base layer iIIa makes the same ofsumcient strength to be practical for making all types of tea balls IIIwhich otherwise would not be possible. A thinner grade or lighter stockof filter sheet layer Ila or IIIa can also be used than would otherwisebe required in making bag I0a if the superficial coating Ila was notprovided.

In Figs. 2b, 2c and 2d there is shown successive steps of the improvedmanufacturing process applied to a filter base layer 2i Ia formed of aparchmentized paper, Cellophane or the like base layer, perforated at2IIc and having an upper surface 2Iib on which a superficial coating orlamina I2a is formed from spread partially fused plastic I2 embodyingthe invention to provide heat sealing filter sheet material III, theparchmentized paper base layer 2i Ia being of the type used for cookingpurposes. Clogging up the perforation 2Iic may be eliminated whenproviding the coating I2a by an additional step (not shown) of blowingair upwardly through the layer 2Iia to clear the perforation 2Iic beforethe partial fusion" of said coating l2a takes I place.

material II, III and 2 described above. Here again the superficialcoating |2a is retained by' an absorption thereof on portions of theupper surfaces of the cotton strands of the side 3llb forming the gauzelayer 3| la as a pervious structure without substantially decreasing theoriginal porosity of said filter cotton gauze base layer 3| la. a r

The superficial coating I2a also serves to increase the tensile strengthof heat sealing, filter sheet material 2 and 3 so that the base layermaterials HM and 3lla, respectively, may be thinner than is practicallyrequired when such coating [2a is not used.

Each of the heat sealing filter sheet materials Ill, 2 and 3 remainflexible and may be coiled up like sheet material ll described above,and any one of said sheet materials II, III, 2| l or 3 may be utilizedfor forming the bags Illa by providing permanently fused joint seams inthe entire construction or in part thereof and for making complete teaball in with string handles l3 and tags it in the same manner asdescribed above.

If desired the fused edge portions may be impressed or embossed bysuitable die (not shown) with word, legend or symbol IS on applicationof molding pressure during the permanent fusing of the seam joint lllbas shown in Fig. 5.

It will thus be seen that there is provided a package, package makingmaterial and a method for producing the latter in which the severalobjects of the invention are achieved and which are well adapted to meetthe conditions of practical use.

As various other possible embodiments of the invention might be made ofthe above invention, and as various changes might be made in theembodiments above set forth, it is to be understood that all mattersherein set forth or shown in the accompanying drawings and described inthe specification is to be interpreted as illustrative and not in alimiting sense.

Having thus described my invention, I claim as new and desire to secureby Letters Patent:

1. A fiexible heat sealing filter sheet for making infusion packagescomprising a filter base layer having a thin dry porous lamina ofthermoplastic material adheringly applied by a partial fusion to oneside of said layer without materially decreasing the original filteringcapacity of the latter, said lamina being capable of forming permanentthermosetting fused seam joints when positioned in face-to face relationand heated above the temperature at which said partial fusion takesplace.

2. In combination, a filter sheet free from thermosetting material and adry porous partially fused coating of thermosetting plastic applied toone side of said sheet, said combination being so constructed andarranged to permit filtering therewith with substantially the samepractical efiiciency as with the filter sheet material without saidcoating, said coating serving as a heat sealing means when portionsthereof are brought in face to face relation and subjected to heat forpermanent fusion above the heat necessary to "partially fuse thecoating. 1

3. A multi-layer sheet material for making bags of infusion packagescomprising a first layer formed of a porous base web, and a second layerformed of a dry foraminous thermosetting plastic film spread and carriedon one side of said web to serve as a heat sealing means and tostrengthen the web without substantially decreasing the I porositythereof, said heat sealing means being effective when portions of thefilm on said web are placed-in face to face relation and thermosettinglyfused.

4. A thin sheet material of the character described comprising aforaminous layer sheet having a filter film of a partially fusedthermosetting resin adhering to one side of said-layer sheet, said layersheet with the film having substantially the same filtering capacity asthe foraminous layer sheet without said film, the latter serving as aheat sealing means when portions thereof are placed in face to facerelation and heated to a degree to cause a final fusion of said portionfor permanent adhesion.

5. A method of producing a heat sealing filter sheet material of thecharacter described consisting in partially fusing" a coating ofthermosetting plastic on one side of a filter base sheet material whileretaining substantially the original porosity of said base sheetmaterial with said coating in condition to permit permanent heat sealingfusion thereof at a temperature above .that of the partial fusing"state.

6. A method of producing a heat sealing filter sheet material of thecharacter described consisting in spreading in a thin pervious layermaterial having thermosetting properties on one side of a filter basesheet, and heating said layer material below the temperature to causepermanent fusion for forming on cooling a dry porous lamina having heatsealing properties at said fusion temperature.

7. The process of manufacturing a heat sealing filter sheet materialconsisting of sprinkling a finely divided polymerizing resin oversuccessive continuously travelling surface portions of a thin filtersheet material, heating said resin to a degree short of final fusion andpressing the same into the surface to form an adhering pervious film onsaid sheet material without materially decreasing the original filteringcapacity of said filter sheet material, and cooling said surface film toa dry condition having heat sealing properties such that when portionsthereof are placed superimposed in face to face relation to form a jointseam and a final fusion heat at a temperature above said heat to formthe adhering film applied such seam is permanently sealed.

8. A filter sheet material of the character described comprising apervious base web structure initially free from the thermo-plasticmaterial yet of sufiicient strength when wet to withstand immersion inhot water without disintegration, and a porous partially fused lamina ofheat sealing material carried to extend over one side of said webstructure, the composition of said web structure and lamina being suchas to be insoluble in hot water, the latter being odorless, tastelessand non-toxic after said immersion.

9. A filter sheet material of the character described comprising a thinporous base web of a structure to permit the ready passage of water in abrewing operation, a finely divided polymerizing resin partial fused"adheringly spread over one side of said web to form an adhering pervioussuperficial coatingwithout substantially reducing the capacity of theweb to permit said ready passage of water.

10. The filter sheet defined in claim 9 in which the wet tensilestrength thereof is suficient to withstand disintegration during saidbrewing operation and which has properties that are insoluble, odorless,tasteless and non-toxic in use for the brewing operation of a beverage.

11. A heat-sealing sheet material for making bags of infusion packages,such as tea-balls, coffee-bags and the like articles comprising a filtersheet layer base having an initial wet strength suflicient to retain theshade and form of infusion packages made therewith when immersed inboiling water without disintegration,

and a dry porous insoluble lamina having thermosetting heat-sealingproperties adheringly applied on at least one side of said layer basewithout substantially decreasing the filtering capacity of said layer,said base with said lamina when serving as containers of said infusionpackages and immersed in boiling water being inherently free fromimparting injurious effects as a food product.

12. A composition product for making bags of infusion packagesconsisting of a porous dry film lamina of a vinyl resin bonded by theapplication of heat at a temperature below that of permanent fusion toone side of a paper which has a high wet strength porous structure forproviding a filtering sheet, said film lamina on the paper being in apartially fused" thermosetting condition capable of forming apermanently thermoset fused seam joint when positioned and pressed inface to face relation with the application of heat above said bondingtemperature.

THEODORE F. MENZEL.

